[开发工具]C++ Primer 学习

第二章 变量和基本类型

自定义数据类型

#include<iostream>
#include <string>

struct Sales_data {
	std::string bookNo;
	unsigned units_sold = 0;
	double revenue = 0.0;
};


int main() {
	Sales_data data1, data2;
	double price = 0; // 书的单价，用于计算销售收入
	// 读入第1笔交易：ISBN、销售数量、单价
	std::cin >> data1.bookNo >> data1.units_sold >> price;
	// 计算销售收入
	data1.revenue = data1.units_sold * price;

	// 读入第2笔交易
	std::cin >> data2.bookNo >> data2.units_sold >> price;

	//计算销售收入	
	data2.revenue = data2.units_sold * price;


	if (data1.bookNo == data2.bookNo) {
		unsigned totalCnt = data1.units_sold + data2.units_sold;
		double totalRevenue = data1.revenue + data2.revenue;
		//输出： ISBN、总销售量、总销售额、平均价格
		std::cout << "The ISBN is " << data1.bookNo << " The total Sales is " 
                  << totalCnt << " The total revenue is " << totalRevenue << " ";
		if (totalCnt != 0)
			std::cout << "The average profit is " << totalRevenue / totalCnt 
                      << std::endl;
		else
			std::cout << "(no sales)" << std::endl;
		return 0;		//标示成功
	}
	else {
		std::cerr << "Data must refer to the same ISBN" << std::endl;
		return -1;		//标示失败
	}
}